(poker) Four cards of the same suit.

(poker) To attempt to pass off a four-flush as a flush. / (figuratively) To bluff.

Of a plant, having four leaves.

(poker slang) four of a kind, aces.

(archaic) Twenty-four. (24)

(card games) Four cards of the same rank.

(rail transport, colloquial) the space between the rails on a standard gauge railway line.

Any four-stroke cycle, such as the Otto cycle, for an internal combustion engine.

plural of four-cycle

plural of four-velocity